It is generally preferred that conventional containers such as squeeze tubes include a snap hinge closure to allow easy opening and closing of the container by the consumer. In this way the cap which closes the container after each use is not separated from the container. When a cap is separated from a container there is the likelihood that the cap can become misplaced. Thus, it is desirable that the cap remain attached to the container when the product is being dispensed from the tube. This form of closure is sometimes referred to as a captive cap.
The dispensing containers and closures are often used with viscous materials such as a dentifrice. Dentifrice compositions experience unique problems which are not found in other materials. One such difficulty in storing dentifrices is the container material must include a suitable barrier layer to prevent absorption of the flavor components and oils. Since the closure remains in contact with the dentifrice for extended periods of time, it is important to minimize the surface area of the cap contacting the dentifrice.
The type of closure that is usually preferred by the consumer is one where the closure is connected to a base by a snap hinge. This form of closure typically includes a hinge where the closure will be biased to an open position during dispensing and biased to a closed position during other times. Although biased to a closed position when product is not being dispensed, a manual force is usually required to snap the cap onto the base to fully close the tube and to seal the exit orifice.
Closures for a tube with a snap hinge have been used in the art for several years. One of the earliest closures of this type is shown in U.S. Pat. No. 1,928,445 which discloses a rubber hinge connecting a cap to a base portion. The base is a threaded annular shaped member attached to a threaded dispensing outlet of a tube. The cap portion is hinged to the base and can be manipulated from a closed position to seal off the outlet of the tube to a fully open position. This closure has a rubber film hinge attached to a base and cap that will bias the cap either in an open position or in a closed position.
Another form of a captive cap for a tube is shown in U.S. Pat. No. 3,933,271. This cap has a base portion attached to the tube and a cap portion connected to the base by a snap hinge. When the cap is opened to a point less than the intermediate position, the cap is biased closed. When the cap is pivoted open to a position past the intermediate position, the cap is biased open. The hinge design provides for this unique action of the cap.
Another type of film hinge for use in connection with a closure is shown in U.S. Pat. No. 4,403,712. This closure has the feature of the cap portion either being biased open or closed. This cap has the added feature that the cap portion is in a closed position, the film hinge is within the profile of the cap. A different type of closure with a snap hinge is shown in U.S. Pat. No. 4,503,991. This is a two part snap hinge to connect the cap to the base. The portion of the closure which seals the dispensing opening of the container has a projection that will fit down into the dispensing opening. The use of a double hinge provides this snap hinge closure with added versatility.
U.S. Pat. No. 4,615,462 discloses an addition example of snap hinge. This hinge is comprised of a main joint and two secondary joints. The main joint stabilizes the cap and base portion while the secondary joints provide the snap action. This is not a film hinge and the hinge parts will not be within the profile of the cap closure when in a closed position. U.S. Pat. No. 4,854,473 discloses a related closure where the hinge is also of a three piece structure. In this closure, the hinge is also of a three piece structure. In this closure, the hinge of the closure will be within the profile of the base cap when the cap lid is in a closed position.
These patents evidence the present state of the art of snap hinge closures for tubes. However, there is not shown a closure that is adapted for use with a tube having a nozzle nor one which has the exit for the delivery of product offset from the centerline of the tube. Further, there is not shown a snap hinge cap that is sufficiently large that the tube can stand on the cap and where the surface of the dispensing part of the cap is angled in order to provide for easier delivery of product. This latter feature is important with regard to toothpastes where the toothpaste is delivered onto a brush. This provides for easier delivery onto a brush. A further advantage is that the cap can be used as a captive cap or as a removable cap, thus satisfying more users.